296 EIGHTH PACIFIC SCIENCE CONGRESS 



with certainty. In the Bay of Bengal a north to south range, the Car- 

 penter's Ridge, which probably is of volcanic origin, is situated to the 

 west of the Andaman-Nicobar chain of islands. The mouths of the 

 Indus in the Arabian Sea and the Ganga-Brahmaputra at the head of 

 the Bay of Bengal have given rise to deep submarine gulleys (Indus 

 Swatch and Swatch of no ground). The presence of the submarine 

 ridges and gulleys substantially influences the circulation in the North- 

 ern Sector of the Indian Ocean, Further, there are widespread forma- 

 tions of coral reefs of the fringing and atoll types throughout the area 

 except on the two sides of the Indian peninsula, although reefs are 

 prominent around southernmost India and Ceylon, the Andaman-Nico- 

 bar group and the Laccadive-Maldive group. The reasons for their ab- 

 sence in most parts of the Indian Coast have not been satisfactorily 

 explained, although it is usually attributed to estuarine influences and 

 silting on the east coast of India and to the upwelling of colder waters 

 on the west coast of India (Sewell, 1937). 



Hydrologically the Bay of Bengal and the Arabian Sea present 

 substantially different features and a careful study and interpretation 

 of these differences might well explain the enormous disparity in fish 

 production between the western and eastern coasts of India, the former 

 contributing to more than two thirds of the total. The Bay of Bengal 

 waters are generally less saline owing to the influence of the large rivers 

 that empty into it. The eastern coast is also characterized by a well- 

 developed estuarine fauna. On the other hand the salinity of the 

 Arabian Sea waters is distinctly higher and the waters generally are of 

 an oceanic character. Owing probably to the upwelling of deeper 

 waters to the surface, the vertical mixing facilitated by the Carlesberg 

 and Murray ridges and the turbulence resulting from strong S. W. Mon- 

 soon winds, the Arabian Sea waters appear to be richer in nutrients 

 having extensive areas of high productivity. It is noteworthy that shoals 

 of plankton feeding fishes like the oil sardine of Malabar (Sardinella 

 longiceps) and the Indian mackerel (Rastrelliger kanagurta) largely 

 contribute to the west coast fisheries of India. 



Post War Interest in Fisheries and Oceanography 



It may be said that the work carried out so far did not form part 

 of any comprehensive programme for the investigation of Indian waters. 

 Collection of further information has continued through the agency of 

 survey ships and subsequent expeditions like that of the Discovery II 

 and the Galathea. With the end of World War II, India, like many 

 other nations of the world, was faced with problems of acute food short- 

 age, and one of the subjects that received governmental attention was 



